This diagnostic image is a 12-lead electrocardiogram (ECG) displayed on standard pink grid paper. The tracing shows a normal sinus rhythm with a heart rate of approximately 95 beats per minute. The primary educational focus is the classic S1Q3T3 sign, a sign of acute right ventricular strain often associated with pulmonary embolism. Key visual findings marked with green arrows include a deep S wave in Lead I, a prominent Q wave in Lead III, and an inverted T wave in Lead III. The QRS complex morphology is otherwise narrow with a normal axis. The chest leads (V1-V6) show normal R-wave progression. This visual material is used in medical education to teach the recognition of ECG manifestations of pulmonary hypertension and acute right-sided heart strain. Target audience includes medical students, residents, and emergency medicine practitioners.

This diagnostic image is a 12-lead electrocardiogram (ECG) recorded at standard speed and voltage. The tracing demonstrates sinus tachycardia, characterized by a rapid heart rate with present P waves preceding each QRS complex. The most clinically significant finding is the 'S1Q3T3' pattern, a classic sign of right ventricular strain. This is visually evidenced by a prominent, deep S wave in Lead I, a discernible Q wave in Lead III, and an inverted T wave in Lead III. Additionally, the precordial leads (V1-V6) show T-wave inversions and ST-segment changes, further supporting a right heart pressure overload morphology. This specific combination of findings is strongly associated with acute pulmonary embolism and right heart strain in the appropriate clinical context. The ECG includes a long rhythm strip at the bottom (Leads V1, II, and V5) to facilitate rate and rhythm analysis.

This diagnostic image is a 12-lead electrocardiogram (ECG) tracing demonstrating a classic S1Q3T3 pattern, a clinical sign of acute right heart strain often associated with pulmonary embolism. The ECG is annotated with black circles and arrows highlighting three primary visual features: a prominent S-wave in lead I (terminal negative deflection of the QRS), a pathological Q-wave in lead III (initial negative deflection), and an inverted T-wave in lead III. The tracing also shows sinus tachycardia, evidenced by a regular rhythm with a heart rate exceeding 100 beats per minute. The QRS complexes are generally narrow and upright in the precordial leads (V1-V6). This illustration is designed for medical students and clinicians to identify specific morphological ECG abnormalities that reflect the pathophysiological stress of the right ventricle against increased pulmonary vascular resistance.

Diagnostic Image: A 12-lead electrocardiogram (ECG) displayed on a standard red grid, demonstrating classic features associated with acute right ventricular (RV) strain. The tracing shows a sinus rhythm with several key diagnostic findings. In the limb leads, an S1Q3T3 pattern is visible, marked with labels: a deep S-wave in lead I (S1), a pathological Q-wave in lead III (Q3), and an inverted T-wave in lead III (T3). In the precordial leads, there are prominent, deep, symmetric T-wave inversions (TWI) extending from V1 through V6, which are also highlighted with arrows. These visual markers collectively illustrate the McGinn-White sign, often associated with acute pulmonary embolism. The ECG serves as an educational tool for recognizing the cardiovascular manifestations of increased right-sided heart pressure and strain.

This diagnostic image is a 12-lead electrocardiogram (ECG) demonstrating a rapid, regular rhythm with narrow QRS complexes, consistent with supraventricular tachycardia (SVT). A hallmark feature of acute right heart strain is visible via the S1Q3T3 pattern: lead I shows a prominent S-wave, lead III displays a significant Q-wave, and there is T-wave inversion also in lead III. The tracing exhibits tachycardia with a rate exceeding 100 beats per minute. These findings are clinically significant for diagnosing pulmonary embolism or other causes of acute pulmonary hypertension in an emergency or critical care setting. The ECG is presented on standard pink grid paper, showing limb leads (I, II, III, aVR, aVL, aVF) and precordial leads (V1-V6) alongside a rhythm strip.